I have a question for my masters-degree paper: where are the trill tresholds upwards and downwards in speed? That is, downwards; when do we (in Hz) start to perceive single events (or durations and no longer an iteration)? And the same upwards; how fast could the iteration become before we no longer perceive an iteration, but a single (blurred) pitch-phenomena? And how is it all related to interval size in pitch (before we start/end to perceive a single stream and not several)?